1. Field of the Invention
The invention is related to a guide/blocking element or device for a lace or similar device, especially intended for lacing a boot. The invention also is related to a boot incorporating such device.
2. Description of Background and Relevant Information
Traditionally, a boot is constituted of a sole and an upper equipped with an opening for the passage of the foot and comprising, on either side of such opening, a collection of guides for one or several laces intended to allow such opening to be closed when a traction is exerted thereupon.
These guides are generally constituted of hooks, but these books cannot retain the lace when it is loosened, or buckles through which the laces pass, the laces passing alternately above and below the plane of each buckle.
A major problem that is posed by all these known guide systems consists of the substantial friction that is produced between the lace and its guide, such that simple traction on the free ends of the lace is not enough to obtain an efficient tightening throughout the entire length of the lacing and one has to exert traction on each end of the lace comprised between two guides in order to obtain an efficient and homogeneous tightening along the entire lacing zone, including at the top of the foot.
This problem is especially critical for boots made of a relatively rigid material, for example, mountain climbing boots made of thick leather or skating boots, having a relatively rigid plastic shell, and for which an efficient tightening is desirable all the way through to the top of the foot.
As a matter of fact, this friction problem is heightened yet further by the length of the lacing zone that is necessary in order to reach the top of the foot.
Moreover, the friction or inadequate sliding of the lace is necessary to a certain extent because the braking effect that results therefrom also acts as an anti-return, facilitating the tightening, especially during the formation of the final bow or knot.
In order to overcome this disadvantage, one has been known to use lace blocking or pinching elements, that are separate from the guides and that are fixed along the edge of the upper, or slidably mounted on the lace. In the latter case, they are cumbersome and not necessarily easy to manipulate since they are mobile.
The document WO 96/24269 discloses a guide/blocking element for a lace constituted of a ring that is mobile with respect to a body, which allows a lace to slide, or inversely, acts as a blocking element for the lace, depending on the position that it occupies with respect to the body.
Such a guide/blocking element certainly has advantages, but it also has disadvantages, especially those stemming from the high costs of a multiple element and multiple material structure. Furthermore, the efficiency of such a system in its guide function mode is not optimum, because the lace passes alternately along either side of the lacing plane, thus resulting in parasitic friction.
In addition, the efficiency of such a blocking system depends enormously on the diameter of the lace to be blocked between the body and its mobile ring.